it'sss normallll It's the oil.... It do the same thing on ALL boxxer and ALLL forks.... We can see it in this picture because the boxxer have black finish. The stanchions on all forks are neverr dry, there have always a very small thin ply of oil. If your fork is dry, she probably need rebuild.
Its light reflecting of the coating.
That is probably just the finnish the black low friction coat has. and it shows up more in this photo than most.
Its cant be finger prints unless he has just smeared his hands all over the stanchions, and then ridden the berm without compressing the fork at all.